Calcium hypochlorite decomposition

Solid Sta.te. The stabiHty of neutral calcium hypochlorite is primarily a function of moisture, lime, impurities, and temperature. Product containing - 7% water may lose 2—3% av CI2 during the first year when stored in warehouses without temperature control in moderate climates. Decomposition produces CaCl2, Ca(C102)2, and O2. 

Dibasic magnesium hypochlorite is more thermally stable than neutral or dibasic calcium hypochlorite. In addition, its decomposition, which starts at - 325° C, is endothermic rather than exothermic as in the case of the Ca compounds. 

By contrast, decomposition of dibasic calcium hypochlorite begins at 265° C to give Ca(OH)2, CaCl, and O2. Dibasic magnesium hypochlorite exhibits a high degree of stabiUty to moisture as shown by the following relative available chlorine losses at 24°C and 80% rh for 60 d Mg(OCl)2 2Mg(OH)2 2%,... 

Calcium Hypochlorite. High assay calcium hypochlorite [7778-54-3] was first commercialized in the United States in 1928 by Mathieson Alkali Works, Inc. (now Olin Corp.) under the trade name HTH. It is now produced by two additional manufacturers in North America (Table 5). Historically, it usually contained about 1% water and 70—74% av CI2, so-called anhydrous product, but in 1970, a hydrated product was introduced (234). It is similar in composition to anhydrous Ca(OCl)2 except for its higher water content of about 6—12% and a slightly lower available chlorine content. This product has improved resistance to accidental initiation of self-sustained decomposition by a Ht match, a Ht cigarette, or a small amount of organic contamination. U.S. production in the 1990s consists primarily of partially hydrated Ca(OCl)2, which is sold as a 65% av CI2 product mainly for swimming pool use. Calcium hypochlorite is also sold as a 50% av CI2 product as a sanitizer used by dairy and food industries and in the home, and as a 32% product for mildew control. 

Calcium hypochlorite Ca(CIO), Water soluble white crystals or powder with strong chlorine odour Non-flammable but can evolve Cb and O2 May undergo decomposition Water spray may be used but evolves Cb gas freely at ordinary temperatures with moisture... 

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials Can catch fire when in contact with porous materials such as wood, asbestos, cloth, soil, or rusty metals Stability During Transport Stable at ordinary temperatures, however when heated this material can decompose to nitrogen and ammonia gases. The decomposition is not generally hazardous unless it occurs in confined spaces Neutralizing Agents for Acids and Caustics Flush with water and neutralize the resulting solution with calcium hypochlorite Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

This oxide catalyses the violent or even explosive decomposition of hydrogen peroxide. This reaction explains the numerous accidents mentioned involving the contact of hydrogen peroxide with rusted iron. Two accidents of this nature dealt with mixtures of hydrogen peroxide with ammonia and an alkaline hydroxide The detonations took place after a period of induction of respectively several hours and four minutes. Iron (III) oxide also catalyses the explosive decomposition of calcium hypochlorite. 

The interaction of a sodium or calcium hypochlorite or phosphorus penta-chloride with urea causes a violent detonation, that has been put down to the decomposition of the nitrogen trichloride formed. 

The compound is very unstable, and its presence may be one of the causes of the observed explosive and apparently spontaneous decomposition of calcium hypochlorite, if produced from magnesia-containing lime (derived from dolomite). 

Although solutions of sodium hypochlorite are useful oxidizing agents, the solid is not very stable. Calcium hypochlorite is used in bleaches, swimming pool treatments, and so forth. The decomposition of OC1- is catalyzed by compounds containing transition metals. 

J. Race, attempting to make ammonium hypochlorite by the double decomposition of ammonium oxalate and calcium hypochlorite, obtained a soln. with its germicidal action greatly enhanced and it was assumed that the unstable ammonium... 

The earliest methods for preparing cyclic a-diazo ketones involved the oxidation of the monohydrazones prepared from a-diketones, generally using mercuric oxide.7,8 Recent modifications of this procedure include the use of calcium hypochlorite in aqueous sodium hydroxide or activated manganese dioxide as oxidants.1 The latter reagent, especially, hoc ms preferable to mercuric oxide. The base-catalyzed decomposition of tile monotosylhydrazoneH of a-diketones has been... 

SAFETY PROFILE A poison. Moderately toxic by intraperitoneal route. Mildly toxic by inhalation. A severe eye irritant. A flammable liquid and ver) dangerous fire haaard when exposed to heat or flame. Explodes on contact with calcium hypochlorite. When heated to decomposition it emits toxic fumes of SOx. See also MERCAPTANS. 

Mutation data reported. Reacts with moisture to form sulfuric acid. Mixtures with calcium hypochlorite + starch + sodium carbonate explode when compressed. Violent reaction with acetic anhydride + ethanol may lead to ignition and a vapor explosion. Incompatible with calcium hypochlorite. When heated to decomposition it emits toxic fumes of SO and Na20. See also SULFATES. 

In practice, the chlorination is effected, not by the use of free chlorine, as such, but by the use of bleaching powderj calcium hypochlorite. The preparation from acetone is by a similar chlorination. In the reaction which takes place, one of the methyl groups is substituted just as in the case of aldehyde, and then a similar decomposition by means of the alkali takes place. 

A small amount of calcium hypochlorite is produced but it is decomposed by adding sodium sulphide. The liquid, after the insoluble matter is removed, is heated to about SO C adding cone, potassium chloride in 10% excess, and the following double decomposition occurs ... 

Calcium hypochlorite undergoes rapid exothermic decomposition on heating above 175°C. Bleaching powder solution reacts with acids with the evoluation of chlorine. 

Swimming pools can be chlorinated by adding either calcium hypochlorite, Ca(OCl)2, or sodium hypochlorite, NaOCl. The active component is the hypochlorite ion, OCl . Because the rate of the following reaction is increased by ultraviolet radiation in sunlight, it is best to chlorinate pools in the evening to avoid the hypochlorite ion s decomposition. 

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